Are there 75 degree head tube/seat tube lugs out there?

I couldn't find anything via google, novacycles.com, bikelugs.com or at henryjames.com. I can probably make 75 degrees work with 74 degree lugs, but I'd rather not if there's something that's already supposed to be 75 degrees.

There may be some but no need. Take a "74" degree seat lug for example. Put a top tube mitered to 74 degrees in the lug with a seat tube and see what it sits at naturally. Its anyones guess what that lug angle will actually be. It wont be exactly 74 I can tell you that, it might even be 75. The angle they are labled is more of an average, they are not exact at all.
I use 74 degree seat lugs on almost all my builds, and I use that to go anywhere from 71 to 77 degrees, no problem at all, especially a seat lug. You just need to be concious of what parts you grind out, and make sure your miter is exactly 75 degrees.

The frame is odd. it is french threaded, french-sized tubes, has unmarked vitus-pattern dropouts, ovaled chainstays, nice work, lots of braze-ons. Steel is thick, takes a 26.0 post. No serial number anywhere. I'll post more pics if anyone's interested.

I suspect the OP lost interest sometime in the last 7 years. That's interesting that you found a bike with 75 degree head angle. I wouldn't have thought that there ever was a production bike with an angle that steep. Not sure it's going to help identify it though

there were some smaller bicycle manufacturers in France at one time. Somewhat unlikely that anyone outside of France would be able to identify that frame, and even there the likelihood is low given the nature of the frame. Interesting seat stay treatment, it looks crushed, but into a really nice flute. Nervex stamped angles into their lugs/bb shells, and had a fairly wide range of products. The French tubing manufacturers slip my mind at this point, but Vitus was around a long time, and those dropouts look like some that they made.

Assuming you are in the U.S., it likely was brought into the country by a serviceman or immigrant